208 COCOA 



CHAP. 



" cocoa -pigment," theobromine, and the essential oil. 

 All these substances are formed if we simply crush fresh 

 cocoa seeds and leave them exposed to the air. This 

 fact shows that the products of the external fermenta- 

 tion do not play any part in the formation of these 

 three important compounds. They are formed by 

 allowing the different constituents of the cocoa seeds to 

 act upon each other, be it by crushing the seeds or 

 killing them by high temperature during fermentation. 



One of the most conspicuous changes which occur 

 in the seeds is the alteration in colour. The violet 

 seeds become reddish -brown and the white seeds 

 yellowish-brown. This change takes place gradually, 

 beginning at the outside and proceeding gradually to 

 the inner parts. This is easily understood if it is 

 remembered that for this chemical process oxygen is 

 necessary, for the air obviously penetrates only gradually 

 into the interior of each seed. This change of colour is 

 caused by the formation of a red compound which has 

 received the name of " cocoa-red" or " cocoa-pigment." 



Whether this compound must be regarded as 

 important from an industrial point of view is still 

 uncertain, for it is not clear whether a larger or smaller 

 amount present in commercial cocoa has any influence 

 upon the quality. The idea, however, that it is the 

 " cocoa-red " which gives cocoa its peculiar aroma is 

 quite erroneous. " Cocoa-red " can be prepared pure 

 from cocoa seeds. It has the appearance of a reddish- 

 brown powder, which is, however, odourless and tasteless, 

 and is therefore not the cause of the aroma which cocoa 

 assumes during fermentation. 



This aroma is due to the formation of another 

 substance, namely, an essential oil. It is obvious that 

 the substance, which gives rise to the aroma, must be a 

 volatile substance, for the aroma develops when the 

 fermented cocoa is boiled, and this strong-smelling 

 essential oil can be obtained pure, or nearly pure, by 



1 The chemical composition of this and other substances is given in 

 Chapter III. 



